red-hot alternator after jump start
Submitted: Wednesday, Apr 04, 2007 at 21:23
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43999
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husky01
can someone smarter than I explain this to me??
wife takes landcruiser ('91 diesel) to work, leaves the lights on - battery 1 dead as a doornail. won't start off second battery because there isn't a manual switch installed (ie: you have to physically swap the batteries). too heavy for wife to lift out.
so, wife calls RAC to jump it. RAC guy phones me and says he jump-started it fine, but the bonnet started smoking up and when he lifted the bonnet the alternator was glowing red-hot.
cruiser gets towed home, and I'm up for a new alternator + expenses, and i suspect a cell is now cooked in the brand new battery.
how can this happen??? If there is a risk of cooking the alternator (maybe charge from 2nd good battery drawing through alternator or something) then why did he not disconnect the dead battery before starting? my common sense says the job should have been done without cooking the alternator?
would someone be able to explain it to me so I am not suspicious.
cheers, husky
Reply By: Wayne (NSW) - Wednesday, Apr 04, 2007 at 21:42
Wednesday, Apr 04, 2007 at 21:42
husky,
If the main battery is dead flat and the vehicle has been jumped started the alternator is trying to charge the battery.
The battery could have also dropped a cell or two.
The only way to check that is with a hydrometer.
The voltage regulator is working overtime trying to get this battery up to voltage. The voltage regulator has probably failed and was charging at 14+ volts and at 100amps. Batteries only want 13.5 volts and 25amps to charge.
If the battery had dropped a cell the alternator will not be able to charge it and will keep trying until it runs red hot.
This is my theory with the info supplied. It is also very simple with out getting into the hi tech stuff.
Wayne
AnswerID:
231704
Reply By: Member - Phil G (SA) - Wednesday, Apr 04, 2007 at 21:49
Wednesday, Apr 04, 2007 at 21:49
Sounds like your battery was down a cell and the alternator was trying to get the voltage up, and kept pumping amps into it.
Hindsight is a wonderful thing. I wouldn't be blaming the tech.
Has your aternator had any work done to it, or is it untouched in 16 years??
AnswerID:
231706
Follow Up By: husky01 - Wednesday, Apr 04, 2007 at 22:11
Wednesday, Apr 04, 2007 at 22:11
the alternator was recon'd 6 months ago, and the batteries are both brand new...
FollowupID:
492685
Follow Up By: Member - DOZER- Saturday, Apr 07, 2007 at 16:06
Saturday, Apr 07, 2007 at 16:06
Mate, everything was working
well till the x factor came along.....it doesnt take much to upset a battery, and flattening it is no 1 on the upset list, especially if it was a calcium battery. Ive seen batteries steaming because the alt wouldnt stop trying to pump it up....and the battery was a cell down to begin with.
I understand you want someone else to take the load off, there is an alternator on ebay at the moment for $80 if you want to take a chance. Ive just been to Supercheap looking at their battery range (20% off today) not cheap those things...
FollowupID:
493066
Reply By: joc45 - Wednesday, Apr 04, 2007 at 22:42
Wednesday, Apr 04, 2007 at 22:42
He didn't put the jump leads round the wrong way, did he?
The diodes in the alternator will conduct in this case, effectively causing a short and lots of heat (and death of alternator).
Generally, if a battery is dead flat, its internal resistance is generally pretty high till it has taken some charge, and the effect of a shorted cell will not take effect for some time after starting to recharge the battery; ie, the charge current will be quite low for some time, making it difficult to draw too much off the alternator.
Just my thoughts, anyway.
Gerry
AnswerID:
231717
Reply By: gen3rules - Thursday, Apr 05, 2007 at 00:03
Thursday, Apr 05, 2007 at 00:03
Hi, Sounds to me like reverse connection causing blown diodes in alternator. Seems to me someone made a booboo jumpstarting your vehicle, have seen this often from people who dont take due care when jumpstarting. I would be taking this up with RAC.
ps. i am an auto spark.
AnswerID:
231726
Follow Up By: Mark Taylor - Thursday, Apr 05, 2007 at 21:12
Thursday, Apr 05, 2007 at 21:12
As an old aiuto sparkie... I'm with reversed battery leads. Just blows the diodes to bits.
Cheers
mark T
FollowupID:
492837
Reply By: Sam from Weipa Auto Electrics - Thursday, Apr 05, 2007 at 07:32
Thursday, Apr 05, 2007 at 07:32
I would put my money on jump starting it the wrong way. but can you prove it? I doubt if the battery is of some quality that jumped backwards or running it flat is going to cause it to drop a cell. the other theory is that the battery was flat he jumped it properly but the battery was so flat the alternator was pumping full output so the main fusebile link starter to smoke as
well as the alternator would be as hot as hell because it is pumping that hard I would charge you're battery check the fusible link and see how it goes.
AnswerID:
231742
Reply By: Mainey (WA) - Thursday, Apr 05, 2007 at 10:38
Thursday, Apr 05, 2007 at 10:38
husky read posts 4 & 5 and take it up with the RAC as they have stuffed up !!!
"So, wife calls RAC to jump it.
RAC guy phones me and says he jump-started it fine,
BUT the bonnet started smoking up and when HE lifted the bonnet the alternator was glowing red-hot."
The alternator was NOT glowing red hot when he connected the cables, to the battery, he would have noticed it, it was only AFTER and BECAUSE he jump started your vehicle the damage was done.
You have every right to be very suspicious
AnswerID:
231778
Reply By: Moose - Thursday, Apr 05, 2007 at 13:30
Thursday, Apr 05, 2007 at 13:30
Something wrong here - how did he start vehicle with bonnet down? What does wife say sequence of events were? If he did start vehicle OK and closed bonnet, how long before it started smoking and he had to re-open?
AnswerID:
231814
Follow Up By: husky01 - Thursday, Apr 05, 2007 at 13:40
Thursday, Apr 05, 2007 at 13:40
wife says he connected (battery pack) directly to the battery (ie: not -ve to engine block)...
next bit a blur as wife gazing at stars or something.... not watching what he did, then he starts engine OK, has a bit of a look around, disconnects leads + drops bonnet, shortly thereafter huge amounts of smoke coming out from under bonnet and he lifts it to see 1 wire to the main battery glowing, and the alternator itself was glowing red.
he didn't have the headlights on at the time (to draw current away). there's a huge amount of black soot on the underside of the bonnet - she must have been smoking alright.
another RAC guy came to look at it this morning, he started it, and we could feel the wire to the main battery warm up, and at the same time the bearing went in the alternator (presumably from previous overheating) and it started making a racket. he had a good look before leaving he basically indicated that he couldnt really help me and that i have been screwed over and wished me luck...
FollowupID:
492774
Follow Up By: husky01 - Thursday, Apr 05, 2007 at 13:42
Thursday, Apr 05, 2007 at 13:42
ps fuseable link seems OK, all the electrics came on this morning anyway so that was not blown.
FollowupID:
492775
Reply By: Sam from Weipa Auto Electrics - Thursday, Apr 05, 2007 at 16:26
Thursday, Apr 05, 2007 at 16:26
You're electrics will come on the alt main wire is not the dash main wire from memory. Still sounds like he jumped started a dead flat battery and the alt was just pumping for dear life heating everything up but if you're bearing is gone you're bearing is gone.
AnswerID:
231844
Reply By: Member - Shane D (QLD) - Thursday, Apr 05, 2007 at 19:31
Thursday, Apr 05, 2007 at 19:31
With out getting into the how's and maybe's of what went wrong with the RAC, all your wife needed was jumper leads, you had a good battery there,as long as it has got an earth EQUAL the the main battery just jump start yourself with only one lead (+ve to +ve)
Shane
AnswerID:
231873
Follow Up By: husky01 - Thursday, Apr 05, 2007 at 22:25
Thursday, Apr 05, 2007 at 22:25
very true my friend, but I am under murphy's law: i have loaned the jumper leads to a mate. the only time in 10 years they have not been in the car is the only time i have ever actually needed them
FollowupID:
492857
Reply By: obee - Friday, Apr 06, 2007 at 19:26
Friday, Apr 06, 2007 at 19:26
Ask your self how many times you needed an RAC man in your lifetime and how much a year it costs. Then ask how much a tow truck costs (no
membership fees there) and get a mobile mechanic to come out to the house. It works for me anyway and I can fix a lot of the problems myself once I get it home.
I knew a pom who was RAC man in England and he was no mechanic just a minimal trained monkey. I dont know what qualifications they use here but then no one seems to check cv's these days especially for important jobs like managing city councils etc.
Owen
AnswerID:
232040
Reply By: Member - DOZER- Saturday, Apr 07, 2007 at 16:11
Saturday, Apr 07, 2007 at 16:11
Does it look melted on the main power wire?? I wonder if the possitive of the battery has contacted the bonnet???
Andrew
AnswerID:
232144
Follow Up By: Graham & Lynne - Monday, Apr 09, 2007 at 19:45
Monday, Apr 09, 2007 at 19:45
Was there" spike protection on jump pak? If not RAC blow you alternater up even if it was correctly connected. You need to phone RAC head officere compensation.
FollowupID:
493316